Homogenizer formed using coherent light and a holographic diffuser

Abstract

A homogenizer for incident light including: a sheet of embossable material including a one micro-sculpted surface relief structure that (i) controls the direction in which light propagates and (ii) homogenizes light with directionality has been formed by replicating in the sheet of embossable material another micro-sculpted surface structure that (i) controls the direction in which light propagates and (ii) homogenizes light with directionality, the another micro-sculpted surface structure having been formed in a photosensitive medium having a refractive index by: (a) generating random, disordered and non-planar speckle in the photosensitive medium using coherent light, the coherent light having been diffused through a holographic diffuser, so as to define non-discontinuous and smoothly varying changes in the refractive index of the photosensitive medium, the smoothly varying changes scattering collimated light into a controlled pattern with smooth brightness variation; and (b) developing the photosensitive medium. Light that is incident on and directed from the homogenizer is directed to an output area, the homogenizer controlling the direction of light that is emanating from the homogenizer to the output area so as to increase brightness in the output area relative to an area outside the output area.